Someone is making pages on my wordpress

How do I get these pages I found on my site deleted? Some kind of spammer put them up there with a .html end which my site does not do. Found them on google webmaster as broken links. I looked all over my root files cant find these pages. I deleted all my other users that are not active and boosted my security to fix this. please help!

http://www.mysite.com/topic125-chlupate-mature-videa-zdrama-ceske-sex-video-hd.html

http://www.mysite.com/post290.html

http://www.mysite.com/topic122-bestiality-seznamka-cz-sexkontakt.html